Terrestrial telescope.



G. l. E. KELLNER. TERRESTRIAL TELESGDPE. MPLNATIQN Hman AUG. 2, 1907.

Cit

UnTTnD sTiiTns PATENT. osnion.

GUSTA? s.. immuni? Kennern-R, or ROCHESTER, NEW Yong, Assionon, :BY MESNE Asscn'sinnrs, To Benson @e :Loran oPTroAL CGMPANY, on noonne'rnn, NEW YORK,

TERRESTRIL TELESGOPE.

secoli.

Specification of etters EEtt.

Patented Got. i2, 1909.

To all witom it 'may concern.-

Be it known i, Guerin.' A. HERMANN lnnLNnn, oit Rochester, in the county oi' Monroe and Seite of New York, have invented certain new and useful improvements in Terrestrlil Telescopes; and l do hereby declare the following to be o inll, clear, and exact descri*d .cn-ot the seine, reference oeing had` to the sccoinpzinying drawings, forming o port of the specification, and to the reference characters marked thereon.

"ll he present invention relates to terrestrial telescopes, tnot is, telescopes employing en objective in combination with en erecting system which erects the image formed by the objective, and en eyepiece to accommodate the eye in looking the image thus prodocce; one `object boing to provide s construction in which two different powers or megniiicstions free from distortion may be obtained without varying the length of the telescope or changing the location of the exit pupil, end another object being 'to provide for other niagniicotions.

'ln tlie'drewingsz-Fignre l is o side View of e telescope constructed in accordance with my invention, in which one forni of telescopic erecting system is employed. Fier. 2 is a longitudine-l section of the seine telescope showing tlie adjustment for one nongnication. Fig. 3 is e. like View showing the adjustment for another inegniiicelion. Fig. e illustrates on embodiment of my invention in which another forni of telescopic erecting system is employed. illustrates en embodiment in which the telescopic system rotatable; and Fig. 6 is a diagrammatic vView ci' e telescopic system.

In this invention there is employed an objective which niay be of the ltind used for telephoto Work consisting of e collective and o dispersive element i and l respectiyeiy, to .obtain n. greet focal .length and retain shortness of the structure. lt is preferably inode telecentric wi vli reference to its image side by placing in or near its focus a collective lens, whose Jfacing ioeus falls on the exit pupil of tloe objective. lf desirable, the i collective lens may be placed so that one of its surfaces, Wliien can lprovided with a cross hair or micrometer, felis into the image formed by objectives By this arrangement the principal rays which cross in the center of esci@ pupil of the objective and which form the axes of the pencils coming from the object, are caused to run parallel to the optical-exis' of the telescope. Coinbined with these parts is en erecting system inv/ing means for varying the power of the telescope without varying the-distance between the system sind the objective preferably in the form of a telescopic system with the common focal point of its lenses shift- 'aole to v'very the power of the telescope, Without changing the distance between the system and the objective, or between the system and a suitable eyepiece 3.

As is Well known, an ordinary telescopic system employs two lensesAsndB (Fig. 6) having their focal points coinciding nt C so that a. ray running parallel to the optical axis, for instance, Ain a distance 71.1 will pass through lens A, then through the common focus C, and through lens B, leaving the letter parallel to'tlie o tical axis in n` distance h2. Tlie ratioo the distances from the exis in which the rey runs before entering and after leaving the system, is the inagnilicetion of the system and is equal to the ratio of the oeel distance ot' the component lenses, e'. e.:

This niognii'icstion is constant in all pairs of conjugate image planes, no matter what their distance is from the system, and as can be proved easily there are only two conjugate ini-age plenos, one on each side of the system which are et equal distances from the outside of the lenses. For instance, if on object H.L (Fie. 6) be moved toward the lens A tlie image H2 will nieve away from lens il and at s certain position of H1 the distance (d2) of the from the lens B will be inst ss great es the distance d from ille lens A. lf now the object H1 be innintni'ned in its place and tlie Wlic-le system is reversed so that tli'e lens B will ybe exactly in the position of lens A there can be obtained a-sharp image in the saine position as before', only the magnification is changed will be seen from the foregoing that s telescopic system may be advantageously employed as an erecting `ystexn for obtainlsa ingdijlereiit powers in terrestrial telescopes .if the' common focal point of the system be zshifted relatively to an objective. This can be accomplished in numerous ways. For instance, in Figs. 2 and 3, I employ a pair of fixed lenses 4 and 5 separated' by a distance different from their focal distances, in this instance less than their focal distances, the focal points being at 4X and ,51 respectively.

Arranged between the lenses is a lens 6 preferably a. collective lens which is movable to form an optical combination with either lens 4 and 5 soas to deflect the rays of onelens and have the focus of the combination fall exactly in the focus of the'- other lens, the.

stead of,acollect1ve lens a dispersing lens 6- is employed and forms a combination'with either' lens to shift the common focus to either point. 'In both of these embodimentsv f it is also ossible to secure other magnifications by s ifting the movable lens and providing' a slight relative adjustment between the erecting system and one oi the other op` tical parts of the telescope, as for instance, by slightly adjusting the eye piece. For this purpose 1t is preferable to provide a con` nectlon between the movable lens and the eye piece whereby the adjustment of .the lens will effect the proper adjustment of the eyepiece. In the embodiment shown, this conv eyepiece, the groove nection is in the form of a sleeve 7 surrounding the tube S to which the optical parts of the telescope are secured and having a cam slot 9 the wall of which engages a projection 10 on the tube'll carrying the adjustable lens. Upon the rotation of the sleeve the pro'ection 10 is caused to move in a longitudmal slot 12 in the tube 8 and the eyepiece is moved by a cam groove 13 formed in the sleeve and engaging a projection 14: on the 13 eing so shaped that in both extreme positions of the adjustable lens the eyepiece will lie in the saine position. The shifting of the common focal point of the telescopic system can be obtained also by rota-ting the telescopic or erecting system inthe manner shown in Fig. 5. Here the lenses la and 5a haveV a common focus F and are mounted within a suitable casing 15 rotatable about an axis 16 so as to position either lens in or 5a toward the object end thus'shift the common focus.

It will be apparent from the foregoing that I have provided a terrestrial telescope,

- in which'it is possible to obtain two ditlerent magniiications without varying the length of the telescope,'as the distances between the erecting system and the objective and between the erectii'ig system and eyepiece are.

caesar constant and that magnifications betweenthese two may be obtained by only a slight' variation in the length of the telescope. This construction is articularly ladvantageous for'usel with or nance, for the reason that it can be quickly nfianipulated to sight an object and 1s less liable to become deranged by shocks duc to firing. It may be further stated, that since in this combination of a telescopic erecting s stem with an objective of the kind describe the principal rays run parallel to the optical ax1s before entering t the two extreme magnilications also leave the erecting system parallel to the optical axis, the conditions which would create distortion of the image are strictly the same and if the distortion is done away with for one magnilication, the image will also be free fromdistortion for the other magnification. And for the magnification between e erecting system and at least for thetwo extremes the inclmationo'f the prin-4 cipal rays tothe optical axis after leaving the erecting system is small enough as not to cause any notable distortion. l

I claim as my invention:

1. In a terrestrialrtelescope, the combina- A ltion with an objectiveand a collec'tive lens arranged so that the exit pupil of the .ob-

' jective falls in its focus, of a telescop1c sys-v tem arranged to erect the image formed by the objective.

, 2. In a terrestrial telescope, the combination with an objective and a collective lens arranged so that the exit pupil of the objective falls in its focus, of a telescopic system arranged to erect the image formed by the objective and having means for'varying.

the power of the telescope.

3. In a terrestrial telescope, the combination with an objective and a collective lens arranged so that the exit pupil Aof the objective falls in its focus, of a telescopic system arranged at a constant distance from the image formed by the objective'to erect said image and having the common focal point ofitslenses shiftable-relatively to the image to vary the power ot; the telescope.

ll. In a terrestrial-telescope, the combination with an objective, a collective lens arranged so that the exit pupill of the objective falls in itsjfocus, and an eyepiece, of a telescopic system arranged between the eyepiece and the collective lens. to erect' the image and having the common focal point`V of its lenses shiftable to vary the power of the telescope without changjng the distance between the system and t e eyepiece and the objective.

5. In a terrestrial telescope, the combina-l tion with an eyepiece and an objective, of

an erecting system arranged between them, embodying two lenses having a common i'ocus, and means for shifting this common focal point relatively to the objective with- 

